Washover overshot



4 Sheetshshee 1 ,M N f1@ Awal 16, 1946. C. BowN ETAL WASHOVER OVERSHOT IFiled oci. 15, 1945 C. C. BROWN ETAL.

April 16, 1946..

wAsHovER vERsHoT y Filed Oct. 15, '1943 4 sheets-sheet' 2 Apnjil 16, 1946. c. c. BROWN ETL wAsHovER ovERsHoT Filed Oct. 15.. 1943 4 Sheets-Shed 5.

April 16, 1946.y c, BROWN ETAL I wAsHovER ovERsHoT vFiled Oct. 15, 1945 4 Sheets-Sheet 4 INVENTORj/t Wm# YBY )l Patented Apr. 16, 1946 wAsHovER ovERsHoT "Cicero C. Brown and Floyd L. Scott, Jr., Houston,

Tex., assignors to Brown Oil Tools, Inc., Houston, Tex., a corporation of Tex.

Application october 15, 1943, serial Naturisme 1o claims. (c1. 294-7102) This invention relates to a'gripplng device `for the purpose of grippingpipes, vrods and similar objects `and has for its general object the provision of such a device which will be better adapted to situations encountered in actual practice. l

.Devices for gripping pipes and.V similar objects havebeen for a long time well known but such devices'havebeen limited in capacity and effectiveness as compared with their size `and have also been limited in their adaptability t0 different situations encountered in actual operation. Thus,v for example; in the case of overshots Vernployed for removing `objects from an opening' such asia Well bore it frequently occurs that the annular space about theoutside of the object to be removed is of suchlimited dimensions that overshots heretofore; devised` have. been .too large to permit their, efficient -`use..` When they are used it not infrequently occursthat` theybecome stuck in the limited annular space available. f The same istrue -of other `types of devices for gripping pipes, rods and the like. y L

Furthermore;` in devices heretofore employed wherein slips are vused for. the purpose of gripping the pipe or otherA object,` the slips have ordinarily been forced -into gripping engagement by relative motion between'a slip bowl or guide having a conical seat and a slip likewise having a conical surface for engaging suchseat. These engaging conical surfaces are designed ordinarily so that they will fit exactly at .some point at which the slip is supposedto fully-engage the object to be gripped.` Howevenif due to wear or `for some other reason the object to be gripped does. not have exactly the dimensions for which the gripping device was designed; or if the gripped device' is of such weight and material that `the slips will bite into or deform the same under the force of the engagement, the conical surfaces wili not be fully engaged, and because lof the thus reduced bearing surface in engagement between the slips andtheir supports, vthe `slips themselves are frequentlylbroken orV the seating surfaces on the slips andonthe ,slip bowls or guides ,are deformed because of excessive loading on the reduced bearingareas. y

It is, thereforela more specific objectof this invention to provide a gripping device of the type referred `to in `which the load capacity of the gripping device will not depend ,upon the` exact size of the memberrto be gripped. l

Another object of this invention is to provide a structure ko1 the type referred to in which the gripping device may be madeof maximum capacity and minimum dimensions so that it may be operated within smaller clearances than devices heretofore employed. It is also noteworthy that in the past such devices in the form of overshots have usually beenmade non-releasable for thereason that the releasing structures heretofore devised have been undependable .and of such a nature that they have been likely to cause the fouling of the device `when used in` spaces off limiteddimensions;

It is, therefore, an object'of this invention to provide an overshot structure with an improved yreleasing device which will be relativelysure in apt tobecome fouled when employed "in relatively small annularspaces or when used in connectionA `with the` .gripping of irregularly shaped objects. i

Other objects and advantages of this invention will become-apparentfrom the following description taken in connection with the accompany- Ving drawings wherein is set forth by way of illustration and example, Vbut not by way of limitation; one embodimentlof therinvention.

In'thel drawings: l -1 f Fig; i1.. is a viewi.partly in sideelevation and partly in vertical cross section `illustrating the upper portion of a. gripping device constructed in accordance withthis invention.`

Fig. 2 is a similar view illustrating the lower portion ofthe same tool and providing a contignuation of the lower portion of Fig. 1.

Figs. 3 and 4 are views similar to Figs`..1 and 2 respectively but showing the device as it is being passed downwardly over a? pipe to be gripped and showing the parts of l the device, in their released position.

Fig. 5shows a transverse cross section taken along the line 5-5 of Fig. 1.

Fig. 6 is a view showing a transverse cross secl tion taken along the line 6--6 of Fig. 1;

Fig. 7 is a fragmentary top plan View of a portion oflth'e slip bowl or guide illustrated in Fig. 8 and showing certain .features of one of the slip seats formed therein.

Fig. 8 is a View partly in side elevation and partly y in longitudinal cross section illustrating `the slip bowl or guide forming a part of the structure shown in Figs. 1 to 4 inclusive.

Fig. 9 shows a .longitudinal cross section 4through the slip retainer ring and slip connections.

through the slip and slip bowl taken along the line IIB-I0 of Fig. 8 and showing the full seating of the cylindrical seat and slide surfaces against each other.

Referring more in detail to the drawings, the tool as illustrated in Figs. l and 2 is suspended upon a pipe I through which the tool is to be operated. On the ylower end -o-f this pipe Vis threadedly secured a collar 2 forming a top connection, and this collar is externally threaded to receive a sleeve 3 which encloses the major portion of the working parts of the tool. Threaded into the lower end of the sleeve 3 is theslip bowl or guide y4 in which the slip supporting guides or seats are formed. The slipkbowl or guide Vcomprising the body 4 is internally threaded at its lower end to receive a pipe 5 or other member which it may lbe desirable to connect thereto.

The slip seats 6 which are formed within'the upper portion of the slip bowl or guide 4 are made cylindrical as distinguished from conical, each seat being formed on its own axis which is inclined with respect to the axis of the holder and which preferably' intersects said axis, and

Vthe outer surfaces of the slips 'I are likewise made cylindrical and of the same radius to iit 'the seats S. Thus in Fig. 8 the'line 6a represents the axis of the cylindrical seat surface 6 in the slip guide 4 and Vit will be seen that this axis is inclined with respect 'to the axis 4a ofthe slip guide 4. The broken lines Scand 6c .in Fig. 8 represent radii of the Vcylindrical surface 6 at its upper and lower ends respectively, these radii being equal in length because o-f the fact that the surface B is cylindrical. A fragmentarytopplan view'showing the cylindrical guide lsurface E is contained in Fig. 7, the upper and lower radiil V(ib and 6c being likewise shown 'in this gure as `being of Aequal length. .In this figure lalso `the shoulder "6d is shown at the lower end of the cylindrical seat surface' and the retaining radial rside walls are indicated as lying between the vsolidline. Y6e at the 'upper end of the cylindrical seatsurface 6 and the 'dotted line '6j at the `lower end thereof. Inasmuch as the arcs struck about the radii bb and 6c are :of equal .-length, *thev Vradial retaining surface between the upper edge'zscand the lower edge Bf at Athe opposite `edges of 'thecylindrical seat surface 6 wouldnot bevisiblein'Fig. 7 except in dotted lines 7as illustrated. One such surface,

however, is illustratedat 6g in Fig. 8. It will thus be seen .that the outer surfaces of the slips I will at all timesseat fully against the seat surfaces 6 regardless of the vertical position of the slips. somewhat larger dimensions than that for which the too-l was desi-gned so that'theslips come into gripping engagement with the member while they are still a substantial distance up in their seats 6, vthey will kstill have a, full'bearing between their outer surfaces and the .slip seat surfaces 6. YThis is "clearly indicated vin Fig'. -l0'of thefdrawings in which the radiusof the .cylindrical seat'surface 6 is indicated at the 'pointfof the section by the line 8h and the radius of'tthe gripping portion of the slip "'I iszindicated at 1a. .Referring to Fig. 'I it will be seen that the iside walls^of"tl1e slip guides or seats aremade 4radial-with lrespect to the axis of the cylindrical zsurface vforming lthe slip seat `and that they, therefore, converge'inwardly. The vertical edges of the-'slips are made of similar conformationv so that when vthe slips are inplace within their respective seatsthey will be held against radial or lateral movement away from their -seats, Aalthough'longitudinal Thus, if the member t0 V10e 'gripped iS 0f i" I2 and the slips I are suspended is moved uptheir inner faces.

Ywardly Vas the two members engage.

'gage the buttress type threads II and 2i.

movement with respect to their seats will be freely permitted. Downward movement of the slips will be limited by the upwardly facing shoulder at the lower end of each slip guide or seat.

The individual slips are provided with suitable teeth 8 on their inner surfaces so that they may grip the pipe or other object in such a manner as to Vmanipulate it in the .desireddirection. In the case of thev teeth illustrated 'these are arranged vertically so as to make possible the trans- Y mission of rotary force to the object to be gripped.

In the case of a pipe such as illustrated in Fig. 4 where a definite external shoulder is present, such slips may also be used to exert a very substantial lifting force on the pipe, but if lifting `force alone against a smooth cylindrical surface be desired, then the teeth 8 on the slips might be arranged horizontally in a manner well known to persons skilled in the art. Any number of slip seats may be provided in the seat bowl to receive a predetermined number o-f slips. Ordinarily three or four .slips will be employed.

Each of the slips 'I is also formed with a stem 9 which extends upwardly and vis formed with a T-shaped head Ill on its upper end fitting into a T slot II in a slip retaining ring I2. This slip retaining ring is slidably mounted within the sleeve 3 and may be rotatably supported through the medium of a ball bearing -I3 Within the lower end of a sliding operating sleeve I4. It will be seen that the balls forming the ball bearing I3 may be inserted thro-ugh a suitable opening in the sleeve I4 into the complementary grooves or races formed in the exterior of the slip retaining ring I2 and in the interior 0f the sleeve I4. After the insertion of the balls this opening would be closed by means ofa suitable plug I5.

Secured to the upper end of the sleeve I4 is an element I which might be termed a ratchet sleeve having downwardly facing .buttress type threads Il on its outer surface. This sleeve may be threaded or otherwise securedxwithin the sleeve I4 as illustrated, and vthen lockedthereto .by means of a set screw I8y or the like.

The lower portion of the tting `2 inside the sleeve 3 is provided .with a series ofvcircumferentially spaced windows I9 in which are positioned radially movable dogs 20 vhaving upwardly facing segmental buttress type threads 2I formed on These dogs Vare at all times urged radially inwardly ,by means of a circumferentially extending spring 22.

From the foregoing it will be seen that when the sleeve `I4 from which the slip retaining ring wardly within the sleeve 3, the buttress type threads II will engage Within the segmental threads ZI on the dogs 20 moving these dogs out- After the members are engaged with each other the dogs 20 will be moved inwardly into full engagement with the threads II by means of the spring 22. When the parts are in this position the slips 'I will be suspended within the upper portions of their seats as illustrated in Fig. 4 and .willfnot grip a member such as the 'pipe`23 which maybe positioned within the tool at the time.

Inorder to dsengage the parts 'I6 and 2li from Aeach 'other so that the slips may .move downwardly within the slip'support 4 and engage a pipe such as the pipe 23, it is necessary to provide a means whereby the sleeveV I4 and its associated parts may be held against rotation while the sleeve 3`and the fitting 2 are rotated to disen- For this purpose there have been provided a plurality of circumferentially spaced friction springs,` 24 which may bereferred to as bow springs and which are located within the sleeve I4. These springs have their opposite ends secured as by means of rivets or the like to' a pair of float; ing'rings 26 and 21. AThesespring 24 are adapted to receive and frictionally gripa pipe suchas the pipe 23 as illustrated in Fig. 3 so that when the major portion of the tool including the tting 2 and the sleeve 3 is rotated, the springs 24 and their associated rings 2E and 21 will be Africtionally held against rotation. In order thatthis holding force might be transmitted to thefsleeve I4, there are inserted in the sleeve I4 and secured thereto between the springs 24 a plurality of siegmental blocks 4or keys 2-8; These may be secured in place by any desired/means such as thescrews Now if the device be lowered over a pipe in the manner illustrated in Figs. 3 and 4, the slips 1 upon striking some enlargement in the pipe 'such as illustrated at 30 will be urged upwardly toward an upper position' within their seats. This is, of course,ac'companied byY an upward move- *I ment of the sleeve I-4 and the member I6 carry'- ing the buttress threads I1. This member entering between the dogs' 20 will cause the buttress threads I1 to engage the'buttress threads 2| and thereafter suspend thev sleeve I4 and the dogs 1 in such upper position.

Itfwill be appreciated, of course, that the parts may be placed in this upper position before being engaged over an elementfsuch as the pipe 23 if sodesired. i J

Having passed the tool over the pipe 213 or other member to be gripped' and having placed it in a position where it is desired to grip thepipe 2i,`

the major portion of the tool is then 'rotated by means of the suspending pipe I while the sleevev I4 and the element |16 are held against rotation by means of the springs 24. .This relative rotation between the parts I6 and 20 williresult in disengagementofthe buttressftype threads I1 and 2|, whereupon an upward movement of the pipe I and its associatedparts including the slip shoumer thereon, the niet result will be than the movement of the springs andthe associated rings 26 and 21 is stopped untilthe keys 28 come in contact with the ringV 21.` .Thereupon further movement tends to straighten out tliesprings 24 and move them upwardly. `:The lower ends of the springs are, of course, anchored to the ring 21 but the upper lends o f the springs together with the ring 26 are freeto move upwardly and thus permitthe springs to straighten out until their central portionshave moved outwardly far `enongh `to permit the entry of the pipe or the passage fof' the shoulder thereon. Thelsame thing occurs when the device isbeing moved up'- wardly ralong the pipe and a shoulder thereon is engaged by `the springs 24.` that instance, however, the` ring 26'will continue to be moved upwardly byjthe'V engagement of the keys 28` wherea'sfthe :ring 21 will be free to move downwardly with respect to the sleeve I4 until the springs A24 Ihave expanded suiilciently to allow the "shoulder on the pipe to pass. Thus it'will be seen that the springs in each case are allowed to eX- springs cannot under any circumstance move in- Wardly into the lpath'vfofthe pipe being engaged or ashoulder thereonlpyet both ends 'of the springs arefree to move* in an' axial direction with' respect tothe tool asth'ecentral portionsof the i springs are ileiied outwardly in` passing over a pipe orashoulder thereon;

It hasbeen found thata tool constructed in accordance with `the foregoing description may be support 4 will result in. an inward movement of Y the slips 1 so that they willv engage the pipe 23 and grip the same. I

YIef after pulling upon the .pipe 23 or making other attempts to manipulate it in the desired manner it is found impossible to dislodge it orit is desired for some other reason to disengage the tool from the pipe 23, this may be accomplished by merely lowering the tool with respect tothe pipe 23. When the tool'is lowered the springs 24 which are in frictional engagement with the pipe 23 will tend to remain stationary and when the keys 28 engage the upper end of the ring 21 this engagement will tend to arrest downward movement of the sleeve I4 and the slips 1, Continued downward movement of the tool will again engage the buttress type threads I1 and 2| with each other whereupon the slips `will "be held in their released upper positionsin their seats and will not grip the pipe 23. The tool may thenv be removed from the pipe 23 by an upward lifting force. l I

It is to be noted in connection with the springs Z4 that both ends of each spring are secured against radial movement so that neither end of any spring may bemoved radially inwardly to foul the tool;v Itis further to be noted that when Ythe tool'is moved overa pipe or the like sothat at an angleto the raxis of the slip bowl, and` made with an-unexpectedly thin wall section so that Ait maybe employed where the annular `clear-` ance raboutthe memberfto be grippedis fvery smallwDue te the formation of the slips and'slip seats 'Within the slip support, the slips will always be in full engagement'` with their seats' and the excessive 'stresses which might otherwise be placed upon the s lips and their seats in the event `the member to be engaged isnotexactly the proper size for the'tool or in the event that the slips -bite into such member more than anticipated will `Means has also `been provided where-by the slips may be positively 'held out of gripping engagement` at all times desired yet may be re` leased `for gripping whenever the occasion arises. AIf desired, after the'slips have been brought into gripping engagement, they may be readily released by aV simple downward movement of the tool with respect to the member gripped.

From the foregoing it will be appreciated that a tool has been provided which is fully capable of carrying out all of the objects and advantages sought by this invention. r

Having described ourinvention, Weclaim:

M1. In a device for gripping pipe orthe like, a slip bowl and slip means having cooperating cylindrical guide and slide surfaces' respectively, said surfacesv being-,formed on anaxis disposed means for Yreleasably supporting the vslip in a portion of the guide where it will not be in en -gagement -with'the mem-ber t'o be gripped, said means beingengageable by relative axial movement andreleasa-ble by relative rotary movement of its respective parts, said means including a circmnferentially threaded Velement and a plurality vof lcircumferentially spaced members .disposedpabout the circumference of :'saidelement, each having a'tlirea'ded-portion engaging the vthreaded circumference -of Ysaid element, and resilient means urging said members radially into Aengagement withsaid element.-

,2. Ina device for gripping pipe -or theflike, a slip bowl and slip means-having Vcooperating cylindrical guide and slide 'l surfaces respectively, said surfaces being formed' on an axisrdisposed atV an angle toV the axisV o f the slip bowl, -means slidable axially with said slips and rotatable with respect thereto, parts having coacting buttress typethreads carried on said means and on said slip bowl respectively, cone of said threaded'parts being movable radially towardvand away from the other, one of said parts consisting of anr'annular member and the other ofsaidrparts consisting .of vaplurality of circumferentially spacedelements engaging the iirst part at a vplurality of circumferentially spaced Aregions and' means for .urging said one part radially'in'a. direction to `engage the other.

3. In a device for gripping-pipe or the like,

a slip holder and a slip havingcooperating cylindrical guide and slide fsurfacesfrespectively, saidsurfaces being formed onl an axisdisposed at an angle to the axis of the slip holder, means slidable. axiallywipyh `said slips and rotatable with Vrespect thereto, parts vhaving.coating buttress of said slidable means-.and make possible the disengagement of said threadedfparts. l Y

4. In a tool adapted'to be llowered 4into l.a well and manipulated therein, a pair v'of parts relatively movable to manipulate the tool, means for moving one of said parts, and akfriction anchor associated with the other part-and adapted to engage a surface within the welll-for frictionally holding saidother part against movement, said friction anchor comprising bowed friction leaf spring means, andmeans on said other Ipart for engaging one end of said spring means and dragging said end of the spring means therewith'while .lj t,

leaving the other end of said spring means free to move within the llimits of the resiliency of the spring means. Y v f Y 5. In a tool adapted to -be lowered into a. well and manipulated therein, a pairY of parts relatively movable `to manipulate the tool, means for moving one of said parts, and a frictionanchor associated with the other part and adapted to engage a surface within the well for frictionally holding said other .part against movement, saidy friction anchor comprisinga laterally buckled friction member, and lost .motion means for engaging with .said other part that end of .said laterally buckled member which isthe leading end as the tool is moved in one direction -or the.A

holding said other. Dart against movement, said atacan friction anchor vcomprising a longitudinally extending bowed` friction leaf spring, afring -at1each end of said spring and secured thereto, both vrings being free of said other-part, anda :key on'said other part `between said rings, -whereby regardless of whether said spring is moved upwardly or downwardly while it is in'frictional. engagement withV a surface Withinthe well, the ring at that vend of the spring which happens to be the leading end of said springwill engage said key to anchor such leading end of said spring against movement with respect to said other part while leaving the trailing end of said spring free for longitudinalmovement with respect to said other part vregardless of the direction of movement of the-spring.

7. In a tool adapted to be lowered into a well and Vmanipulated therein, afpair .of parts relatively movable to manipulate the tool, means for moving one of said parts,v and a friction anchor associated with the other part adapted to engage a surface within the well for frictionally holding said other part against movement, said friction anchor comprising .-a longitudinally extending bowed friction leaf spring, a pair of anchor rings .one secured to each of the opposite ends of said spring and both free of said other part, a key on said other part Vbetween said rings, whereby upon'movement of saidother par-t in either direction while said spring is in frictional engagement with a surface within the'welL' said key will engage the ring at that end which for the direction of ,movement of the tool is .the leading end of said spring to anchor Asaid spring against longitudinal movement with respect to said other part While leaving the trailing end of said spring free for-such vlongitudinal movement regardless of the direction of movement of the spring, said key on said other part also being in'engagement with said spring adjacent its ends to hold said .other part against rotative movement with respect to'said spring.

8. Ina tool adapted vto belowered into a well and manipulated thereinya'pair of parts relatively movable to manipulate the tool, means for moving one Vof said partaiand `a friction anchor associated withthe other' part and adapted to engage a surface within the well for frictionally holding said otherpart against movement, said friction'anchor comprising 'a laterally buckled friction Vmember extending longitudinally of said other part, a pair of anchor rings'secured to the opposite ends of -said laterally buckled friction member respectively and both free' of said other part, a key on said other part between said rings, whereby upon longitudinal movement of said other part within the wall while said laterally buckled friction member is in engagement with a surface within the well, said key will engage the ring which is secured to that end which for the direction of movement of the tool is the leading end of said laterally buckled friction member to anchor such leading endof said member with respect to said other part while leaving the trailing end of such member free tomove longitudinally, regardless ofthe direction of movement of said other part. l

9. In a tool adapted to be lowered into a well and manipulated therein, a pair of parts relatively movable to manipulate the tool, means for moving one of said parts, and a friction anchor associated with the othcr'part andadapted to engage a surface within the well for frictionally holding said other part against movement, said friction anchor comprising va laterally' buckled friction member, a pair of rings, one secured to each of the opposite ends of said laterally buckled friction member and both free of said other part, a key on said other part .between said rings ,whereby upon longitudinal movement of said other part said key will engage the ring at that end which for the direction of movement of the tool is the leading end of said laterally buckled friction member to anchor such leading end against movement with respect to said other part while leaving the trailing end of said laterally buckled friction member free for such longitudinal movement with respect to said other part regardless of the direction of movement of said other part, said key being in engagement with said laterally buckled friction member to anchor cIcERo c. BROWN.y FLOYD L. SCOTT, Jn. 

